@velartrill
As I'm part of the problem here maybe I can provide some insight.

I tried going through the instructions on the GNU website on how to correctly license your project under GPL. They are quite complicated and I couldn't really tell what data do I need to put where - do I need these silly headers in all files, just one or none is fine? Do I need a separate file with a contributors list? Which parts of the license should I modify by adding the name of the project, my name or whatever else? How do I indicate that the license doesn't encompass some of the that have their own licenses? Does any of this impact the legality?

Maybe the answer is nothing above really matters, and I should've just slapped the license on and left it at that. But the manual scared me of, and I just slapped MIT on, because I knew this was at least common practice. For the record I tried this twice.

Maybe I'm just stupid, but I'd say the instructions not being clear enough are at least part of the problem. :/